UPDATE 6:57 AM: Most arrivals and departures were on time Monday morning at Indianapolis International Airport after an electrical problem at the Atlanta airport on Sunday caused delays across the nation.

Power was restored at Hartsfield-Jackson Atlanta International Airport around midnight.

Delta Flight 1757 to Atlanta at 7 a.m. was canceled. Other flights arriving from Atlanta were listed as on time. Check you airline's schedule before leaving for the airport.

EARLIER: As of 5:20 p.m. Sunday, seven flights scheduled to depart from Indianapolis International Airport were delayed due to a major power outage at Hartsfield-Jackson Atlanta International Airport.

A spokesperson for the Indy airport had no other information about the delays.

The Atlanta airport is the busiest in the world, and the power outage occurred there just before 1 p.m. The Federal Aviation Administration ordered all flights scheduled to arrive in Atlanta to halt due to the impact of the outage on airport terminals.

Departures out of Atlanta are also delayed.

"The FAA tower can operate normally, however, departures are delayed because airport equipment in the terminals is not working," the FAA said.

U.S. Customs and Border Protection also announced that international flights were being diverted to other airports.

The cause of the power outage is under investigation. Georgia Power said it expects to have returned power to the airport by midnight Monday.